User:Frédéric Dardel/Sandbox

transfer RNA or tRNA are stable, structured RNA that are present in all living cells. They participate in the process of protein translation by the ribosome. tRNA carry a specific aminoacid esterified on their 3'-OH group (the acceptor end). They also carry a specific triplet sequence, the anticodon, which pairs with its complementary codon on the messenger RNA, within the ribosome.

Cells have usually have sets of tRNA corresponding to all 20 standard aminoacids, with anticodons capable of pairing with the 61 "sense" or coding codons. The secondary structure of tRNA is conserved, with a classical cloverleaf fold comprising four stems. In three dimensions, tRNA adopt an "L" shape, with the acceptor end on one end and the anticodon on the other end.

After incorporation of the aminoacid into the nascent protein chain by the ribosome, tRNA need to be esterified again with their cognate aminoacid, a process which is catalysed by a family of enzymes called aminoacyl-tRNA synthetases.